C# と VB.NET の質問掲示板

■No55792 (ホエホエ さん) に返信
> タイトルにもありますが、コンボボックスの表示テキストを
> 中央、右寄り表示したいのですが、テキストボックスのように
> TextAlignプロパティがないためできません。

これでどうでしょうか。VB2008 + 32bit版XPで検証しています。
(Win2000 以下や、64bit動作の場合はこれでは駄目かも)

Imports System.Runtime.InteropServices

Public Class Form1
    <StructLayout(LayoutKind.Sequential)> Private Class ComboBoxInfo
        Public Size As Integer
        Public RectItem As Rectangle
        Public RectButton As Rectangle
        Public ButtonState As Integer
        Public ComboBoxHandle As IntPtr
        Public EditBoxHandle As IntPtr
        Public ListBoxHandle As IntPtr
        Public Sub New()
            Me.Size = Marshal.SizeOf(Me)
        End Sub
    End Class
    Private Declare Function GetComboBoxInfo Lib "USER32" _
        (ByVal hwndCombo As IntPtr, ByVal cbi As ComboBoxInfo) _
        As <MarshalAs(UnmanagedType.Bool)> Boolean
    Private Declare Auto Function SetWindowLong Lib "USER32" _
        (ByVal hWnd As IntPtr, ByVal nIndex As Integer, _
         ByVal dwNewLong As Integer) As Integer
    Private Declare Auto Function GetWindowLong Lib "USER32" _
        (ByVal hWnd As System.IntPtr, ByVal nIndex As Integer) As Integer
    Private Const GWL_STYLE As Integer = -16
    Private Const ES_RIGHT As Integer = 2

    Private Sub SetRightAlign(ByVal combo As ComboBox)
        Dim ci As New ComboBoxInfo()
        If Not GetComboBoxInfo(combo.Handle, ci) Then Return
        If ci.EditBoxHandle = IntPtr.Zero Then Return
        Dim style As Integer = GetWindowLong(ci.EditBoxHandle, GWL_STYLE)
        SetWindowLong(ci.EditBoxHandle, GWL_STYLE, style Or ES_RIGHT)
    End Sub


    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
        SetRightAlign(ComboBox1)
    End Sub
End Class

C#だとこれであってますか？
[StructLayout(LayoutKind.Sequential)]
        private class comboBoxInfo
        {
            public int Size;
            public Rectangle RectItem;
            public Rectangle RectButton;
            public int ButtonState;
            public IntPtr ComboBoxHandle;
            public IntPtr EditBoxHandle;
            public IntPtr ListBoxHandle;
            public void New()
            {
                this.Size = Marshal.SizeOf(this);
            }
        }
        [DllImport("user32.dll")]
        private extern static bool GetComboBoxInfo(IntPtr hwindCombo, comboBoxInfo cbi);
        [DllImport("user32.dll")]
        private extern static int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
        [DllImport("user32.dll")]
        private extern static int GetWindowLong(IntPtr hWnd, int nIndex);
        private const int GWL_STYLE = -16;
        private const int ES_RIGHT = -8;

        private void SetRightAlign(ComboBox combo)
        {
            comboBoxInfo ci = new comboBoxInfo();
            if(!GetComboBoxInfo(combo.Handle, ci))
            {
                return;
            }
            if (ci.EditBoxHandle == IntPtr.Zero)
            {
                return;
            }
            int style = GetWindowLong(ci.EditBoxHandle, GWL_STYLE);
            SetWindowLong(ci.EditBoxHandle, GWL_STYLE, style); 
        }

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            SetRightAlign(comboBox1);
        }

■No55806 (マサヤ さん) に返信
> C#だとこれであってますか？
これでは求める結果にならないと思います。元質問者は言語を指定していないので、
VB でも C# でも F# でも JScript でも、言語自体の縛りは無さそうですけれども。


>>    <StructLayout(LayoutKind.Sequential)> Private Class ComboBoxInfo
> [StructLayout(LayoutKind.Sequential)]
>         private class comboBoxInfo
間違いではありませんが、クラス名は大文字で始めるのが慣習です。


>>         Public Sub New()
>             public void New()
コンストラクタの記述が間違っています。
C# の場合は「public comboBoxInfo()」ですね。


>>    Private Const ES_RIGHT As Integer = 2
>        private const int ES_RIGHT = -8;
定数値が変わってしまっています。ES_RIGHT は 0x0002 です。


>>        Dim style As Integer = GetWindowLong(ci.EditBoxHandle, GWL_STYLE)
>>        SetWindowLong(ci.EditBoxHandle, GWL_STYLE, style Or ES_RIGHT)
>             int style = GetWindowLong(ci.EditBoxHandle, GWL_STYLE);
>             SetWindowLong(ci.EditBoxHandle, GWL_STYLE, style); 
肝心の ES_RIGHT が指定されていません。このコードで最も重要な箇所なのに…。

>shuさん
>魔界の仮面弁士さん
他人の質問で恐縮ですが勉強させていただき、ありがとうございます。
修正いたしました。

[StructLayout(LayoutKind.Sequential)]
        private class ComboBoxInfo
        {
            public int Size;
            public Rectangle RectItem;
            public Rectangle RectButton;
            public int ButtonState;
            public IntPtr ComboBoxHandle;
            public IntPtr EditBoxHandle;
            public IntPtr ListBoxHandle;
            public ComboBoxInfo()
            {
                this.Size = Marshal.SizeOf(this);
            }
        }
        [DllImport("user32.dll")]
        private extern static bool GetComboBoxInfo(IntPtr hwindCombo, ComboBoxInfo cbi);
        [DllImport("user32.dll")]
        private extern static int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
        [DllImport("user32.dll")]
        private extern static int GetWindowLong(IntPtr hWnd, int nIndex);
        private const int GWL_STYLE = -16;
        private const int ES_RIGHT = 0x0002;

        private void SetRightAlign(ComboBox combo)
        {
            ComboBoxInfo ci = new ComboBoxInfo();
            if(!GetComboBoxInfo(combo.Handle, ci))
            {
                return;
            }
            if (ci.EditBoxHandle == IntPtr.Zero)
            {
                return;
            }
            int style = GetWindowLong(ci.EditBoxHandle, GWL_STYLE);
            SetWindowLong(ci.EditBoxHandle, GWL_STYLE, style | ES_RIGHT); 
        }

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            SetRightAlign(comboBox1);
        }